[115.02] Jet directions in Seyfert galaxies

We present the study of the relative angle between the
accretion disk (or radio jet) and the galaxy disk for a
sample of Seyfert galaxies selected from a mostly isotropic
property, the 60\mum flux. For each galaxy we have a pair
of points (i,\delta), which are the inclination of the
galaxy relative to the line of sight, and the angle between
the jet projected into the plane of the sky and the host
galaxy major axis, respectively. This data is combined with
a statistical technique to determine the distribution of
\beta angles in 3 dimensions, the angle between the
jet and the host galaxy plane axis. The analysis of the
data, not differentiating between Seyfert 1's and 2's,
showed that the observed distribution of i and \delta
values can be well represented by a homogeneous
\beta-distribution in the range
0\circ\leq\beta\leq90\circ. However, when we
distinguished between Seyfert 1's and 2's, the models could
not represent Seyfert 1's adequately. It was necessary to
introduce viewing angle restrictions, that a galaxy can only
be recognized as a Seyfert 1 if the angle between the jet
and the line of sight (|\phi|) is smaller than a given
angle \phic and that the galaxy inclination i is
smaller than an angle ic, in order to have statistically
acceptable models. This is a direct and independent
confirmation of the underlying concepts of the Unified
Model.

We discuss two main lines to explain the misalignment
between the accretion disk axis and the host galaxy disk
axis: i) feeding of the accretion disk by aligned inflow
from the galaxy disk, with the posterior misalignment of the
accretion disk (e.g. warping by self-irradiation
instability, by the Bardeen-Petterson effect, or by a
misaligned gravitational potential of a nuclear star cluster
surrounding the black hole); ii) feeding of the accretion
disk by misaligned gas inflow (e.g. misaligned minor
mergers, capture of individual molecular clouds from the
host galaxy).

This work was supported by NASA grants.

The author(s) of this abstract have provided an email address
for comments about the abstract:
schmitt@stsci.edu